1. Field of the Invention
The invention relates to an axial-flow turbine with at least one row of bowed guide vanes and at least one row of rotor blades.
Bowed guide vanes are, in particular, employed in order to reduce the secondary losses which occur due to the deflection of the boundary layers in the guide vanes.
2. Discussion of Background
Turbines with bowed guide vanes are known, for example, from DE-A-37 43 738. In this publication, vanes are shown and described whose bowing over the vane height is directed towards the pressure side of the respectively adjacent guide vane in the peripheral direction. Also known from this publication are vanes whose bowing over the vane height is directed towards the suction side of the respectively adjacent guide vane in the peripheral direction. This is intended to reduce both radial boundary layer pressure gradients and boundary layer pressure gradients extending in the peripheral direction in an effective manner and, in consequence, to reduce the aerodynamic blading losses. To whichever side of the adjacent vane the bowing of this known vane is directed, it extends precisely in the peripheral direction in each case. This means that in the case of the cylindrical vanes represented, their leading edges at least are located in the same radial plane over the height of the vane.